Metastatic breast cancer with osteolytic skull lesions suspected to be multiple myeloma

ABSTRACT

We report a case of breast cancer with osteolytic skull lesions which mimicked osteolytic lesions in multiple myeloma. A 60-year-old female was admitted to our hospital due to confused mentality. Laboratory tests showed the findings of an increased calcium level, kidney failure, and anemia. Multiple osteolytic lesions were detected in the ribs, spine, humerus, and pelvis on X-rays. The skull showed the punched out sign. Accordingly we initially suspected multiple myeloma; however, monoclonal protein was not detected in serum and urine and the number of plasma cells was not increased in bone marrow examination. In bone marrow examination, metastatic cancer was detected and biopsy revealed breast cancer. Finally, breast cancer with multiple metastases including those to bone, liver, and lung was diagnosed. Therefore, when a patient presents with multiple osteolytic lesions, we need to consider metastasis from solid cancer in the differential diagnosis as well as multiple myeloma.